Isoimmunization is unlikely to be the cause of hemolysis in ABO-incompatible but direct antiglobulin test-negative neonates

Clinical value of combined predictors of RET%, γ-GT, LDH in the ABO neonatal hemolytic disease

Objective

The purpose of this study is to examine the prognostic significance of the amalgamated indicators, reticulocyte percentage (RET%), lactate dehydrogenase (LDH), and γ-Glutamyltransferase (γ-GT), in neonatal ABO hemolytic disease.

Methods

A total of 137 hospitalized children with pathological jaundice were included. Based on their medical conditions, they were categorized into two groups, hemolytic (67 cases) and non-hemolytic (70 cases). Pearson linear correlation and binary logistic multivariate analysis were used to analyze LDH, γ-GT, RET% and hemolysis. Furthermore, the predictive value of the combined predictors of RET%, LDH, and γ-GT on ABO neonatal hemolytic disease was evaluated using the ROC curve analysis.

Results

The laboratory indexes of the two groups were subject to analysis using binary logistic regression to identify suspicious influencing factors. The study revealed that RET%, LDH, and γ-GT were independent risk factors for hemolysis. Pearson linear correlation analysis indicated a positive correlation between LDH and γ-GT with RET% (r = 0.529, P < 0.01; r = 0.526, P = <0.01, respectively). Furthermore, the predictive value of each combined predictor was obtained using the ROC curve, and it was observed that combined predictor L (RET% + LDH + γ-GT)>L1 (RET% + LDH)>L2 (RET% + γ-GT).

Conclusion

Combined predictor L (RET% + LDH + γ-GT)demonstrate its optimal diagnostic efficacy, offering a novel approach towards diagnosing early-onset ABO hemolytic disease of the newborn.

Rates of phototherapy among ABO-incompatible newborns with a negative direct antiglobulin test

OBJECTIVE

We analyze phototherapy rates after implementation of a Hyperbilirubinemia Clinical Pathway (HCP), which placed full-term ABOi DAT negative newborns on the low risk phototherapy nomogram, rather than medium risk, as previously done.

STUDY DESIGN

A chart review was performed for ABOi newborns born ≥36 weeks gestation between January 2020 and October 2021. Primary outcome measures were rates of phototherapy across pre- and post-intervention groups and among DAT negative newborns.

RESULTS

There was an increased proportion of newborns assigned to the low risk curve after the intervention. There were no significant differences in phototherapy rates among the intervention groups, although there was a non-significant decrease in phototherapy rates among DAT negative newborns after the intervention. There were no increases in adverse outcomes.

CONCLUSIONS

Providers adhered to the guidelines after implementation of the HCP. ABOi DAT negative newborns can be viewed as low risk for hyperbilirubinemia requiring phototherapy.

A retrospective comparison of phototherapy need in O-B versus O-A incompatibility in a single Saudi institution

BACKGROUND

ABO incompatibility is a major risk factor for neonatal indirect hyperbilirubinemia (NIH), requiring treatment. It has been shown that there are racial differences in direct antiglobulin test (DAT) positivity and phototherapy need in the O--B versus (vs) O--A incompatibility. The comparison between the O--B and O--A incompatibility is not well studied in Saudi Arabia.

AIMS

We aimed to compare DAT positivity and phototherapy need in O-B vs O-A incompatibility in Saudi Arabia.

METHODS

This retrospective cohort study was conducted in one Saudi hospital. We included a convenience sample of neonates born between 01 January 2013 and 31 December 2021. We included healthy neonates admitted to the nursery care unit only, born at≥38 weeks gestation, and had normal G6PD levels. Neonates that had no G6PD level measurement or lost follow-up post-discharge were excluded. The data span was the first 14 days of life.

RESULTS

A total of 611 neonates met our inclusion criteria. Positive DAT was more prevalent in the O-B than the O-A incompatibility [43.5% vs 29.2%, p <  0.001). A greater odd of phototherapy need was observed in the O--B vs O-A incompatibility across various strata. Readmission for NIH, use of 360° exposure phototherapy, or intravenous immunoglobulin administration was more prevalent in the O-B than the O-A incompatibility (13.2% vs 5.0%, p <  0.001). A logistic regression analysis revealed that the O-B incompatibility modified the association between DAT positivity and phototherapy need.

CONCLUSIONS

The O-B incompatibility had a mediator effect on the relationship between DAT positivity and the need for phototherapy in the study population, which emphasizes that the O-B and O-A are not the same from the NIH point of view.

ABO hemolytic disease of the newborn: a need for clarity and consistency in diagnosis

The diagnosis of ABO hemolytic disease of the newborn (ABO HDN) has been the subject of considerable debate and clinical confusion. Its use as an overarching default diagnosis for hyperbilirubinemia in all ABO incompatible neonates regardless of serological findings is problematic and lacks diagnostic precision. Data on hemolysis indexed by carbon monoxide (CO) levels in expired air (ETCOc) and blood (COHbc) support an essential role for a positive direct antiglobulin test (DAT) in making a more precise diagnosis of ABO HDN. A working definition that includes ABO incompatibility, significant neonatal hyperbilirubinemia, and a positive DAT is needed to gain clarity and consistency in the diagnosis of ABO HDN. Absent a positive DAT, the diagnosis of ABO HDN is suspect. Instead, a negative DAT in a severely hyperbilirubinemic ABO incompatible neonate should trigger an exhaustive search for an alternative cause, a search that may require the use of targeted gene panels.

Direct antiglobulin test in the prediction of hyperbilirubinemia and predischarge bilirubin levels in infants with mother-infant blood type incompatibility

BACKGROUND

This research evaluated the association between the mother-infant blood type or rhesus (ABO or Rh) incompatibility, the pattern of neonatal jaundice, and serum bilirubin (TSB) values obtained prior to discharge from hospital of healthy born neonates with gestational age >34 weeks and birth weight >2000 g.

METHODS

We utilized a laboratory and neonatal database to identify the cord blood ABO/Rh and direct antiglobulin test (DAT) and TSB measured during hospitalization and re-admission with hyperbilirubinemia for phototherapy treatment. We used hour-specific TSB to analyze the TSB levels for ABO/Rh compatibility and isoimmunization using chi-square, analysis of variance, and regression models.

RESULTS

Of the 901 infants studied, 158 (17.5%) had ABO/Rh incompatibility, including 27 with positive DAT. Hyperbilirubinemia was diagnosed in 33.3% DAT positive, 6.9% DAT negative, and 4.6% of infants with compatible blood types. Increased predischarge TSB was observed in DAT positive infants at 48-72 h of postnatal age (P < 0.001). After controlling for age at TSB testing and weight loss percentage, multiple regression analysis did not show any impact of ABO/Rh incompatibility and DAT results on the predischarge TSB levels.

CONCLUSION

Blood type incompatibility increases the frequency of hyperbilirubinemia only in the DAT-positive infants. Irrespective of the isoimmunization status, it does not significantly affect the level of predischarge TSB.

Different Types of Minor Blood Group Incompatibility Causing Haemolytic Disease of Neonates in one of the National Children's Medical Centre in China

Purpose

To review the neonatal cases with different types of minor blood group incompatible haemolytic diseases in China, and to improve the clinical understanding and management.

Materials and Methods

Seven cases from January, 1st, 2013 to December 31st, 2019 were searched out and reviewed retrospectively. All clinical data and laboratory findings were collected.

Results

There were totally seven cases enrolled including three cases of MNS, three of Diego, and one of Kidd combined with Rh, anti-RhE incompatibility. Among the seven cases, two had intrauterine transfusion, two underwent exchange transfusion, five received intravenous immune globulin, five cases developed anaemia, and three of them had transfusion. But among them, only four were found to have positive antibody screening and three were confirmed HDN with antibody types antenatally.

Conclusion

The clinical presentation is diverse. Antibody screening followed by the technique of peak systolic velocity in the fetal middle cerebral artery (MCA-PSV) helps to filter out the severe cases.

Extreme neonatal hyperbilirubinemia and kernicterus spectrum disorder in Denmark during the years 2000-2015

OBJECTIVE

To determine the incidence and etiology of extreme neonatal hyperbilirubinemia, defined as total serum bilirubin (TSB) ≥450 µmol/L, and kernicterus spectrum disorder (KSD) in Denmark between 2000 and 2015.

STUDY DESIGN

We identified all infants born between 01.01.2000 and 31.12.2015 with TSB ≥450 µmol/L, ratio of conjugated to TSB <0.30, gestational age ≥35 weeks, and postnatal age ≤4 weeks, using Danish hospitals' laboratory databases.

RESULT

We included 408 infants. The incidence of extreme neonatal hyperbilirubinemia among infants with gestational age ≥35 weeks was 42/100,000 during the study period with a seemingly decreasing incidence between 2005 and 2015. Twelve of the 408 infants developed KSD, (incidence 1.2/100,000) Blood type ABO isohemolytic disease was the most common explanatory etiology.

CONCLUSIONS

Our study stresses the importance of a systematic approach to neonatal jaundice and ongoing surveillance of extreme neonatal hyperbilirubinemia and KSD.

Severe ABO Hemolytic Disease of the Newborn Requiring Exchange Transfusion

ABO incompatibility (ABOi), the most common cause of hemolytic disease of the newborn (HDN), is nearly always mild and treatable with phototherapy. Reports of ABOi HDN requiring neonatal exchange transfusion are extremely rare since the inception of modern guidelines. Here, a case of ABOi HDN clearly met criteria for exchange transfusion. An O-positive African American mother delivered a B-positive neonate that quickly developed hyperbilirubinemia. The neonatal DAT was positive from anti-B and anti-A,B, and maternal IgG titer was 1024. Double volume exchange transfusion resulted in a favorable outcome. Given early discharge of newborns, further understanding of factors predicting severe disease is needed.

The Direct Antiglobulin Test: Indications, Interpretation, and Pitfalls

The direct antiglobulin test (DAT; sometimes referred to as the "Coombs" test) continues to be one of the most widely used assays in laboratory medicine. First described about 70 years ago, it is elegantly simple in design, yet it is widely complex in its applications and interpretations, and it is prone to false-positive and false-negative results. The overall objective of our review is to provide practicing pathologists with a guide to identify situations when the DAT is useful and to highlight disease-specific shortcomings as well as general pitfalls of the test. To accomplish these goals, this review will discuss the following: (1) the history of the DAT, (2) how the test is performed in the clinical laboratory, (3) clinical situations for its use, (4) its interpretation, and (5) the pitfalls associated with DAT assays, including causes of false positivity.

The role of UGT1A1 promoter polymorphism and exon-1 mutations in neonatal jaundice

OBJECTIVE

In the present study, we investigated the effects of promoter polymorphism and an exon-1 mutation (G71R) in the UGT1A1 gene in neonates with unexplained hyperbilirubinemia and direct Coombs-negative [DC(-)] ABO incompatibility.

METHODS

Two-hundred term neonates in their first week of life and without additional icterogenic factors were included in the study. Neonates with a serum total bilirubin (STB) level ≥17 mg/dL constituted the hyperbilirubinemia group (n = 100), while the control group comprised healthy neonates with a STB level <12.9 mg/dL (n = 100). The cases were further subdivided into unexplained hyperbilirubinemia (n = 50), ABO(+) hyperbilirubinemia (n = 50), ABO(-) control (n = 50), and ABO(+) control (n = 50) groups on the basis of the presence or absence of DC(-) ABO incompatibility. DNA was isolated from peripheral blood and amplified by PCR, and UGT1A1 gene promoter and exon-1 were sequenced to verify sequence alterations.

RESULTS

The frequency of TA6/6, TA6/7, TA7/7, and GGA/GGA, GGA/AGA, AGA/AGA genotypes was found to be 63.5%, 21%, 15.5%, and 91.5%, 8%, 0.5%, respectively. While both heterozygous and homozygous TA7 polymorphism increased risk of hyperbilirubinemia in the ABO(+) hyperbilirubinemia group (heterozygous OR 16.76, 95% CI:3.52-79.70, p < 0.0001; homozygous OR 6.81, 95% CI:1.98-23:42, p = 0.002), only heterozygous TA7 polymorphism increased jaundice risk (OR 5.08 95% CI:76-14.65, p = 0.003) in unexplained hyperbilirubinemia. But, the coexistence of G71R mutation and promoter polymorphism or G71R mutation and DC(-) ABO incompatibility did not increase the severity of hyperbilirubinemia (p > 0.05).

CONCLUSIONS

UGT1A1 gene promoter polymorphism and G71R mutation are possible risk factors for Turkish neonates with DC(-) ABO incompatibility and unexplained hyperbilirubinemia.

Carboxyhemoglobin levels as a predictor of risk for significant hyperbilirubinemia in African-American DAT(+) infants

OBJECTIVES

To compare the degree of hemolysis in a group of direct antiglobulin test (DAT) positive (pos) African-American (AA) infants as measured by carboxyhemoglobin corrected (COHbc) for carbon monoxide in ambient air to a similar group of DAT negative (neg) ABO incompatible infants and a group without blood group incompatibility. To determine if COHbc is a better predictor of significant hyperbilirubinemia than DAT status.

STUDY DESIGN

A prospective study of 180 AA infants from the Well-Baby Nursery of an inner city community hospital, all of whose mothers were type O pos. Infants (60) were ABO incompatible DAT pos, 60 were ABO incompatible DAT neg and 60 were type O(+). Blood for COHbc was drawn at the time of the infants' initial bilirubin and the infants' precise percentile on the Bhutani nomogram was calculated.

RESULT

Mean COHbc of type O(+) infants was 0.76±0.21 and 0.78±0.24% for ABO incompatible DAT neg infants (P=0.63). Mean CoHbc for the ABO incompatible DAT pos infants was 1.03±0.41% (P<0.0001 compared with both type O and DAT neg infants). Optimal cutoff on the receiver operating characteristic curve for COHbc to determine the risk for being in the Bhutani curve high risk zone was COHbc >0.90% (area under the curve(AUC) 0.8113). This was similar to the AUC of the receiver operating characteristic curve using any titer strength of DAT pos as a cutoff (0.7960).

CONCLUSION

Although not greatly superior to the titer strength of DAT pos, COHbc is useful in determining if the etiology of severe hyperbilirubinemia is a hemolytic process.

Neonatal BO Incompatibility Is Associated With a Positive Cord Blood Direct Antiglobulin Test in Infants of Black Ethnicity

ABO hemolytic disease of the newborn occurs almost exclusively in infants of blood group A and B who are born to group O mothers. Positive Direct Antiglobulin Test (DAT) can identify those infants who are at risk of developing the ABO hemolytic disease. Earlier studies have suggested that BO incompatibility is associated with a positive DAT in black infants. In this study we sought to determine whether ABO incompatibility type could be associated with a higher rate of DAT positivity or clinical hemolytic disease. We reviewed the electronic medical records of all ABO-incompatible births over a 2-year period. There were 1537 ABO-incompatible births during the study period. DAT was more commonly positive among BO incompatible (21.5% in BO vs. 14.8% in AO, P=0.001) and black (18.8% in blacks vs. 10.8% in nonblacks, P=0.003) infants. DAT positivity was significantly associated with both severe hyperbilirubinemia (P=0.028) and hemolytic anemia (P<0.001). BO incompatibility was significantly associated with hemolytic anemia, but not severe hyperbilirubinemia, in the infants tested.

Comparison of the direct antiglobulin test and the eluate technique for diagnosing haemolytic disease of the newborn

Objective

The direct antiglobulin test (DAT) is an important tool for identification of haemolytic disease of the newborn (HDN) caused by erythrocyte immunization. Although this test has been used for decades, accurate insights into its diagnostic properties and optimal use in the diagnosis of HDN are limited. We aimed to gain more insight into the diagnostic properties of the DAT for HDN by comparing it with erythrocyte eluate screening.

Design and methods

DAT and erythrocyte eluate screening was performed in umbilical cord blood of neonates obtained from 317 consecutive deliveries. Clinical jaundice was scored 4–6 days after delivery for the determination of HDN.

Results

In 21 neonates a positive DAT and in 61 neonates a positive eluate screening was found, while only 4 cases of HDN were observed. For the overall population the positive predictive value (PPV) and specificity of the DAT for HDN were 10% and 93% respectively and in the population of neonates with abnormal post-partum jaundice population the PPV and specificity were both 100%. The DAT missed two cases of HDN. These missed cases were, however, positive in the erythrocyte eluate screening.

Conclusion

The detection of clinically irrelevant ABO immunization limits the specificity of the DAT and eluate for HDN in ABO-incompatible pregnancies. For optimal use, the DAT should be requested only in cases of jaundice and be interpreted in the context of ABO-incompatibility. Finally, a negative DAT does not rule out HDN. When clinical suspicion is high, an eluate should be added following a negative DAT.

How to use: the direct antiglobulin test in newborns

The direct antiglobulin test (DAT) detects the presence of immunoglobulin, complement or both bound to the red blood cell membrane. The test, historically called the 'Coombs test', was first described in 1945 by Cambridge immunologist Robin Coombs. Suspected haemolytic disease of the newborn, due to either Rhesus disease or ABO incompatibility, is one of most common reasons for requesting a DAT in newborns. In this article, we discuss the physiological background and technological background of the DAT. We also provide a clinical framework for a rational approach to the use and interpretation of the DAT in newborns.

Common hematologic problems in the newborn nursery

"Common red blood cell disorders encountered in the normal newborn nursery include hemolytic disease of the newborn and resultant hyperbilirubinemia, anemia, and polycythemia. A less frequent clinically relevant hematologic issue in newborns to be covered herein is thrombocytopenia."

The role of carboxyhemoglobin measured with CO-oximetry in the detection of hemolysis in newborns with ABO alloimmunization

OBJECTIVES

To evaluate carboxyhemoglobin (COHb) values measured with a CO-oximeter (Roche-cobas b 221) in jaundiced newborns with or without hemolysis and healthy controls in order to assess whether COHb measurement determined with a CO-oximeter could be used as an indicator of hemolysis in newborns with ABO alloimmunization.

METHODS

A total of 86 term newborn infants were prospectively studied. The study cohort consisted of three subgroups: 18 infants with ABO HDN, 21 infants with hyperbilirubinemia without hemolytic disease who required phototherapy, and 47 healthy controls. The COHb, bilirubin, and Hb levels were measured.

RESULTS

The three subgroups did not differ significantly with respect to birth weight, gestational age, gender, Apgar score, or mode of delivery. The ABO HDN infants had significantly higher COHb values than the healthy controls (median 2.4% versus 1.3%, p < 0.0005) and the group with hyperbilirubinemia without hemolytic disease (median 2.4% versus 1.3%, p < 0.0005), although the infants with hyperbilirubinemia without hemolytic disease did not have significantly higher COHb values compared with the healthy controls. The cut-off value of 1.7% COHb had 72% sensitivity and 97% specificity for confirming hemolysis in ABO alloimmunization.

CONCLUSIONS

Our data show that COHb values determined with CO-oximeters are higher in newborns with hemolysis than in those without hemolysis. COHb measured with CO-oximeters could be used to confirm hemolysis in infants with ABO alloimmunization.

Hyperbilirubinemia, hemolysis, and increased bilirubin neurotoxicity

Increased hemolysis in the presence of severe neonatal hyperbilirubinemia appears to augment the risk of bilirubin neurotoxicity. The mechanism of this intensifying effect is uncertain. In direct antiglobulin titer (DAT) positive, isoimmune hemolytic disease, the bilirubin threshold at which neurotoxicity occurs appears to be lower than in DAT-negative hyperbilirubinemia. In other hemolytic conditions, the hemolysis may simply facilitate the development of extremely high serum bilirubin levels. Whether the hemolytic process per se exerts an independent effect or whether a very rapid rise in serum bilirubin might lead to greater penetration of the blood-brain barrier is unclear. In this review, we survey the synergistic role of hemolysis associated with severe hyperbilirubinemia in the potentiation of bilirubin-induced neurotoxicity and suggest methods of identifying at-risk babies with increased hemolysis to allow for their increased surveillance.

Diagnostic laboratory technologies for the fetus and neonate with isoimmunization

Maternal-fetal blood group incompatibility is common but less commonly results in hemolytic disease of the fetus and newborn (HDFN). HDFN is associated with greater peak bilirubin, at an earlier age, and for longer duration than other causes of hyperbilirubinemia. It poses a substantial risk for kernicterus and accounts for the majority of exchange transfusions for hyperbilirubinemia. Advances in diagnosis and management are described, from identification of the alloimmunized pregnancy by maternal ABO and Rh typing, antibody screen (indirect Coombs test), identification and titration; laboratory evaluation of the maternal-fetal unit with a critical maternal antibody titer to prompt fetal antigen status determination; assessment of fetomaternal hemorrhage by conventional Kleihauer-Betke testing or by flow cytometric methodology; to antenatal management of isoimmunization and fetal status assessments using the systems of Liley, Queenan, and serial Doppler fetal middle cerebral artery peak velocity measurements. The utility of laboratory diagnostics in the approach to hemolysis in the neonate, including hematology, chemistry, and peripheral blood smear review, is reviewed. The goal of management, to deliver a healthy infant at or near term, is attained for the majority of cases using current modalities; future directions include noninvasive genotyping of fetal blood from maternal serum to fully eliminate RhD alloimmunization and HDFN; and development of prophylaxis and intervention strategies for non-RhD alloimmunizations for which immune globulin is currently unavailable.

Blood types and ABO incompatibility

Using the Punnett square and having an understanding of the relationship between genes and blood types will assist you in explaining blood type inheritance to parents and answering their many questions. Using this tool, nurses can show parents what is happening during the division of genes and how blood type genes are expressed.

[Neonatal ABO incompatibility underlies a potentially severe hemolytic disease of the newborn and requires adequate care]

ABO allo-immunization is the most frequent hemolytic disease of the newborn and ABO incompatibility is present in 15-25 % of pregnancies. True ABO alloimmunization occurs in approximately one out of 150 births. Intensity is generally lower than in RhD allo-immunization. We report on three cases showing that ABO allo-immunization can lead to severe hemolytic disease of the newborn with potentially threatening hyperbilirubinemia and complications. Early diagnosis and adequate care are necessary to prevent complications in ABO incompatibility. A direct antiglobulin test is the cornerstone of diagnosis and should be performed at birth on cord blood sampling in all group infants born to O mothers, especially if of African origin. Risk factor analysis and attentive clinical monitoring during the first days of life are essential. Vigilance is even more important for infants discharged before the age of 72 h. Every newborn should be assessed for the risk of developing severe hyperbilirubinemia and should be examined by a qualified healthcare professional in the first days of life. Treatment depends on the total serum bilirubin level, which may increase very rapidly in the first 48 h of life in cases of hemolytic disease of the newborn. Phototherapy and, in severe cases, exchange transfusion are used to prevent hyperbilirubinemia encephalopathy. Intravenous immunoglobulins are used to reduce exchange transfusion. Treatments of severe hemolytic disease of the newborn should be provided and performed by trained personnel in neonatal intensive care units.

Hemolysis and hyperbilirubinemia in antiglobulin positive, direct ABO blood group heterospecific neonates

OBJECTIVE

We quantified hemolysis and determined the incidence of hyperbilirubinemia in neonates who were direct antiglobulin titer (DAT)-positive, ABO heterospecific, and compared variables among O-A and O-B subgroups.

STUDY DESIGN

Plasma total bilirubin (PTB) was determined before the neonates were discharged from the hospital and more frequently when clinically warranted, in neonates who were DAT positive with blood group A or B and with mothers who had blood group O. Heme catabolism (and therefore bilirubin production) was indexed by blood carboxyhemoglobin corrected for inspired carbon monoxide (COHbc). Hyperbilirubinemia was defined as any PTB concentration >95th percentile on the hour-of-life-specific bilirubin nomogram.

RESULTS

Of 164 neonates, 111 were O-A and 53 O-B. Overall, hyperbilirubinemia developed 85 neonates (51.8%), and it tended to be more prevalent in the O-B neonates than O-A neonates (62.3% versus 46.8%; P = .053). Hyperbilirubinemia developed in more O-B newborns than O-A newborns at <24 hours (93.9% versus 48.1%; P< .0001). COHbc values were globally higher than our previously published newborn values. Babies in whom hyperbilirubinemia developed had higher COHbc values than the already high values of babies who were non-hyperbilirubinemic, and O-B newborns tended to have higher values than their O-A counterparts.

CONCLUSIONS

DAT-positive, ABO heterospecificity is associated with increased hemolysis and a high incidence of neonatal hyperbilirubinemia. O-B heterospecificity tends to confer even higher risk than O-A counterparts.

[What blood tests to predict severe hyperbilirubinemia in early maternity discharge?]

OBJECTIVES

To evaluate the efficiency of blood tests (blood group, direct antiglobulin test) to assess severe hyperbilirubinemia in full-term newborns, delivered from mothers with rhesus negative or O group and to determine clinical and biological factors that may improve the prediction characteristics of this blood test.

PATIENTS AND METHODS

We included all the full-term newborns, delivered from mothers with rhesus negative or O group, in a tertiary maternity ward, in 2005, from January6th to December31st.

RESULTS

One thousand and ninety-two children were included. Newborns of A, B or AB group delivered from a mother 0 were at increased risk of presenting severe hyperbilirubinemia (OR=2.35 [1.22-4.52]). The negative predictive value was 96%. Yet, the determination of the Coombs test does not increase NPV.

CONCLUSION

Systematic performance of blood test for newborns delivered from mother with O group does increase the ability to predict severe hyperbilirubinemia in a newborn infant. Direct antiglobulin test systematic performance remains questionable.

Identification of neonates at risk for hazardous hyperbilirubinemia: emerging clinical insights

Hyperbilirubinemia is the most common condition requiring evaluation and treatment in neonates. Identifying among all newborns those few at risk to develop marked hyperbilirubinemia is a clinical challenge. Clinical, epidemiologic, and genetic risk factors associated with severe hyperbilirubinemia include late preterm gestational age, exclusive breastfeeding, glucose-6-phosphate dehydrogenase deficiency, ABO hemolytic disease, East Asian ethnicity, jaundice observed in the first 24 hours of life, cephalohematoma or significant bruising, and history of a previous sibling treated with phototherapy. It is increasingly apparent that the etiopathogenesis of severe hyperbilirubinemia is often multifactorial, and emerging evidence suggests that combining risk factor assessment with measurement of predischarge total serum or transcutaneous bilirubin levels will improve hyperbilirubinemia risk prediction.

A comparison of morbidity rates attributable to conditions originating in the perinatal period among newborns discharged from United States hospitals, 1989-90 and 1999-2000

Perinatal conditions account for 60% of US neonatal deaths, yet little is known about rates of morbidity attributable to these conditions. To estimate these rates, we analysed newborn hospital discharges from the National Hospital Discharge Survey. We used International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes to classify discharge diagnoses among a weighted, nationally representative sample of newborns discharged from short-stay, non-federal US hospitals. We compared overall and cause-specific morbidity rates attributable to perinatal conditions (ICD-9-CM 760.0-779.9), as well as the average length of hospital stay among newborn discharges during 1989-90 and 1999-2000. The overall newborn morbidity rate declined from 36.3% in 1989-90 to 33.7% in 1999-2000 (P < 0.01), despite significant increases in high-risk births. The decline can be attributed to significant decreases in the reported rates of jaundice, fetal distress, birth trauma and birth asphyxia. Rates of jaundice decreased from 15.7% to 13.4% (P < 0.01). The average length of stay decreased among newborns with no morbid condition (2.37-2.04 days, P < 0.001) and among those with one perinatal condition (3.11-2.51, P < 0.001), but increased among those with multiple perinatal conditions (8.43-9.98, P < 0.05). Morbidity rates among newborns discharged from US hospitals declined. Shorter newborn hospital stays may have resulted in fewer cases of jaundice being diagnosed before discharge. Stricter diagnostic criteria and changes in obstetric practices may have led to a decline in the rates of fetal distress, birth trauma and birth asphyxia.

Whole blood versus red cells and plasma for exchange transfusion in ABO haemolytic disease

Records of 381 neonates who underwent exchange transfusion (ET) due to ABO haemolytic disease at the Division of Neonatology of Hacettepe University, Ankara, Turkey, between January 1977 and December 2003 were reviewed. Records were kept for the type of blood used in ET, the number of ETs for each infant, adverse event attributable to ET and bilirubin levels before, and 4 and 8 h after each ET. Of 381 infants, 300 were transfused with whole blood, whereas 81 infants were transfused with O red cells suspended in A or B plasma. The re-exchange rate was higher in the whole blood group, compared with the erythrocyte and plasma group. Use of erythrocyte and plasma provided 30% reduction in the number of ETs per patient. Eight hours after the first ET, mean bilirubin levels were 84% of the pre-exchange values in the whole blood group and 73% of the pre-exchange values in the erythrocyte and plasma group (P = 0.001). As the use of O group red cells re-suspended in AB plasma decreased the re-exchange risk compared with O group whole blood, we suggest the use of O red cells re-suspended in AB plasma for the ET in cases of ABO haemolytic disease.

Review of positive direct antiglobulin tests found on cord blood sampling

Until recently, all babies born in Wellington had umbilical cord blood sampling for direct antiglobulin test (DAT). It is considered to be an important test in identifying babies who are at risk of haemolytic disease of the newborn (HDN).

OBJECTIVE

The aim of this review was to examine the utility of positive DAT results and ascertain: -- How many cases required phototherapy? -- Were any babies readmitted for phototherapy? -- Did the positive DAT influence the detection and treatment of HDN?

METHODS

The clinical records of all newborn babies found to have positive DATs by Wellington Hospital Blood Bank, over a 6-month period (January 2001-June 2001) were reviewed. Blood group serological results of all babies that received phototherapy during this period were also reviewed.

RESULTS

Ninety-four babies had a positive DAT, of which 22 (23%) received phototherapy. The incidence of a positive cord blood DAT was found to be 5.5%. In total, 1724 cord blood samples were analysed by Blood Bank over the first 6 months in 2001. Overall 145 babies received phototherapy, 117 were DAT-negative and six were not tested. Six of the 22 (27%) DAT-positive babies that received phototherapy were alerted by a positive DAT, leading to measurement of serum bilirubin (SBR). Twelve of the 22 (55%) were initially alerted by clinical jaundice, leading to measurement of SBR. Two DAT-positive cases were diagnosed antenatally, both were due to anti-D. Overall 10 babies were readmitted for phototherapy, two had a positive DAT. One baby received an exchange transfusion in addition to phototherapy. Two babies that received phototherapy had SBRs in the exchange transfusion range. Eighty-six per cent of the DAT-positive cases treated with phototherapy were due to anti-A. There were four cases of DAT-negative ABO HDN.

CONCLUSIONS

The positive predictive value of a positive DAT for HDN is 23%. The sensitivity was estimated to be 86%. Ten babies required readmission for phototherapy, two of these were DAT-positive. Jaundice, rather than the positive DAT, was the first alert in the majority of cases of HDN requiring phototherapy. Recommendations for testing are discussed but remain controversial in practice. Assessment for hyperbilirubinaemia in all infants early in life is fundamental.

The Emergency Department Approach to Newborn and Childhood Metabolic Crisis

For most emergency medicine physicians, the phrases "newborn workup" and "metabolic disease" are, at best, uncomfortable. This article, however, provides a simple approach to the recognition,evaluation, and treatment of infants with all manners of metabolic issues, including hypoglycemia, inborn errors of metabolism, jaundice, and electrolyte abnormalities. The disorders are grouped based on symptomatology, and have simple guidelines for work-up and management, with an emergency department practitioner perspective in mind.

Understanding severe hyperbilirubinemia and preventing kernicterus: Adjuncts in the interpretation of neonatal serum bilirubin

The serum total bilirubin concentration at any point in time represents the amount of bilirubin being produced minus that being excreted. Hyperbilirubinemia develops when bilirubin production exceeds the body's capacity to excrete it, primarily by conjugation. When extreme, hyperbilirubinemia may lead to the development of free bilirubin, that form of bilirubin which may cross the blood-brain barrier and enter and damage the basal nuclei of the brain. This rare, though devastating complication, may result in irreversible bilirubin induced brain damage termed kernicterus. In this paper, adjuncts to the interpretation of the serum total bilirubin are discussed, with the purpose of singling out those few neonates in real danger of bilirubin encephalopathy. Interpretation of the serum total bilirubin should be performed in conjunction with factors unique to the particular infant being evaluated. Understanding the mechanisms and dangers of severe neonatal hyperbilirubinemia should facilitate recognition of an emergency situation and optimize the speed with which bilirubin testing is performed and blood for exchange transfusion prepared. Hyperbilirubinemia is a condition of major importance and a source of concern to all involved in the management of the newborn. Its prevention and management should be based on the recently revised American Academy of Pediatric guidelines, with special attention paid to neonates manifesting risk factors for kernicterus. Close cooperation between the clinical laboratory and the medical team managing the newborn is an essential component in the management of a hyperbilirubinemic baby.